This invention relates to a drilling machine tool of the type in which a machine tool body has a movable frame which is movable in the three axial directions of a rectangular coordinate system. The movable frame is provided with a working head carrying at least one spindle.
Normally with this type of machine tool the advancing and retreating direction of the movable frame in relation to a workpiece is expressed as the X axis, a direction of travel lateral thereto is expressed as the Y axis, and an upward and downward direction of travel is expressed as the Z axis. The movable frame is positioned by being moved in the Y axial direction and in the Z axial direction to be directed to a point of the workpiece to be drilled. Then, the movable frame is driven in the X axial direction so that the drilling work on the workpiece may be carried out by the spindle of the working head of the movable frame.
This drilling machine tool, however, is inconvenient because the drilling direction is limited to the X axial direction. Thus it is necessary to set the workpiece in a position inclined with respect to the X axial direction in order to drill a hole at an angle on a workpiece. Such an arrangement of the workpiece is troublesome.
A working feed driving mechanism has been proposed which is attached to the movable frame such that an angle thereof may be adjustable, in order to drill a hole at an angle on the workpiece (Japanese Unexamined Patent Publication No. Sho 57-194808.) This arrangement, however, is inconvenient in that it is complicated, since it requires not only a working head feed driving mechanism, but also a moving mechanism for the movable frame provided separately.